NAME

Crypt::OpenSSL::Bignum - OpenSSL's multiprecision integer arithmetic

SYNOPSIS

use Crypt::OpenSSL::Bignum;

my $bn = Crypt::OpenSSL::Bignum->new_from_decimal( "1000" );
# or
my $bn = Crypt::OpenSSL::Bignum->new_from_word( 1000 );
# or
my $bn = Crypt::OpenSSL::Bignum->new_from_hex("0x3e8");
# or
my $bn = Crypt::OpenSSL::Bignum->new_from_bin(pack( "C*", 3, 232 ))

use Crypt::OpenSSL::Bignum::CTX;

sub print_factorial
{
  my( $n ) = @_;
  my $fac = Crypt::OpenSSL::Bignum->one();
  my $ctx = Crypt::OpenSSL::Bignum::CTX->new();
  foreach my $i (1 .. $n)
  {
    $fac->mul( Crypt::OpenSSL::Bignum->new_from_word( $i ), $ctx, $fac );
  }
  print "$n factorial is ", $fac->to_decimal(), "\n";
}

DESCRIPTION

Crypt::OpenSSL::BIGNUM provides access to OpenSSL multiprecision integer arithmetic libraries. Presently, many though not all of the arithmetic operations that OpenSSL provides are exposed to perl. In addition, this module can be used to provide access to bignum values produced by other OpenSSL modules, such as key parameters from Crypt::OpenSSL::RSA.

NOTE: Many of the methods in this package can croak, so use eval, or Error.pm's try/catch mechanism to capture errors.

Class Methods

new_from_word

Create a new Bignum object whose value will be the word given. Note that Bignums created using this method are necessarily between 0 and 2^32 - 1.

new_from_decimal

Create a new Bignum object whose value is specified by the given decimal representation.

new_from_hex

Create a new Bignum object whose value is specified by the given hexidecimal representation.

new_from_bin

Create a new Bignum object whose value is specified by the given packed binary data. Note that objects created using this method are necessarily nonnegative.

zero

Returns a new Bignum object representing 0

one

Returns a new Bignum object representing 1

bless_pointer

Given a pointer to a OpenSSL BIGNUM object in memory, construct and return Crypt::OpenSSL::Bignum object around this. Note that the underlying BIGNUM object will be destroyed (via BN_clear_free(3ssl)) when the returned Bignum object goes out of scope, so the pointer passed to this method should only be referenced via the returned perl object after calling bless_pointer.

This method is intended only for use by XSUB writers writing code that interfaces with OpenSSL library methods, and who wish to be able to return a BIGNUM structure to perl as a Crypt::OpenSSL::Bignum object.

Instance Methods

pointer_copy

This method is intended only for use by XSUB writers wanting to have access to the underlying BIGNUM structure referenced by a Crypt::OpenSSL::Bignum perl object so that they can pass them to other routines in the OpenSSL library. It returns a perl scalar whose IV can be cast to a BIGNUM* value. This can then be passed to an XSUB which can work with the BIGNUM directly. Note that the BIGNUM object pointed to will be a copy of the BIGNUM object wrapped by the instance; it is thus the responsiblity of the client to free space allocated by this BIGNUM object if and when it is done with it. See also bless_pointer.

AUTHOR

Ian Robertson, iroberts@cpan.org

SEE ALSO

perl, bn(3ssl)